Amount of light falling on a surface is measured in?

The amount of light falling on a surface is measured in footcandles, which quantifies illuminance, referring specifically to the intensity of light that illuminates a given area. One footcandle is defined as the illuminance produced by a uniform source of light of one lumen per square foot. This measurement is crucial in lighting design, as it helps determine how well an area is lit for various tasks, ensuring that the lighting levels are appropriate for visibility and comfort.

Lumens quantify the total amount of light emitted by a light source but do not take into account the area over which that light is spread. This makes lumens a measure of total light output, rather than the light hitting a specific surface. Candlepower indicates the intensity of light at a given angle from a source, focusing on the luminous intensity rather than the area covered, and is often used to describe the brilliance of a light source in a particular direction. Color Rendering Index (CRI) is a metric that evaluates how accurately a light source represents colors in comparison to a natural light source, which is unrelated to illuminance measurements on surfaces. Thus, footcandles is the most accurate choice for measuring the amount of light falling on a surface.